1. Field of the Invention
The invention relates to a diagnostic method and a diagnostic device for monitoring the operation of a technical system with an automation system.
2. Description of the Related Art
The maintenance and repair of automation technology systems can be improved if the correct function of subsystems or components is monitored. With a decreasing functionality, action can be taken specifically at the correct point in the system to implement measures for maintenance, upkeep or error correction.
The article “Monitoring of Complex Industrial Processes based on Self-Organising Maps and Watershed Transformations” by Christian W. Frey, Fraunhofer Institute IOSB, dated Mar. 11, 2016, discloses a diagnostic method for monitoring complex industrial processes, in which a self-organizing map is trained for an error-free behavior of the process based on process variables, in other words based on recorded values of measured variables and the values of the controlled variables output to the process. According to Wikipedia dated 4 Mar. 2016, a type of artificial neural network is referred to as a “self-organizing map” (SOM) or “self-organizing feature map” (SOFM). As an unmonitored learning process they are a powerful tool in data mining. Their operating principle is based on the biological knowledge that many structures in the brain have a linear or planar topology. Based on the self-organizing map that is predetermined in accordance with the above article, the subsequent operating behavior is compared with the acquired error-free behavior. In this way, a differing behavior is identified, which can subsequently be analyzed for causes and possible errors in the operation of the process.
The disadvantage with the conventional diagnostic method is, however, that the process variables to be evaluated and their current values are determined by listening into the field bus communication without, in the process, the process variables to be evaluated being selected especially. Process variables that have no relevance to the diagnosis and may therefore falsify the diagnostic statement may therefore disadvantageously also be included in the evaluation for determining a diagnostic statement.